Session files don't currently save the PASeq. You need to save that as a separate PASeq preset file. And then import it at a later date as a separate step.
Ideally you'd like the current PASeq to be saved as a part of the session file. There's an issue with how the PASeq presets are saved that prevents us from embedding them in a session file.
What we will probably do in the future is move towards a solution that saves a 'session' as a folder. There could be several files in side of that 'session' folder that would save everything you would ideally like to be included in an archived session.
Many digitial audio programs work this way. A saved session folder contains multitple audio files along with some kind of session document that contains control settings.